Screw machines of this type are heated, in particular when starting up, from room temperature to a very high operating temperature, generally of between 200° C. and 300° C., so both the respective housing and the respective screw shaft or, in the case of multi-shaft machines, the screw shafts, expand in the longitudinal direction. The screw shaft non-rotatably provided on an output shaft of the gear in each case expands here toward its screw tip, in other words toward the discharge end of the housing. This is easily possible as axial play is present in any case in the region between the screw tip and the discharge end of the housing. It is conventional in practice for the thermally caused expansion of the housing to be compensated in that a slide connection is present at the discharge end, as is known, for example, from EP 0 849 065 A1 (corresponding to U.S. Pat. No. 5,865,472).
It is often necessary, for operating or structural reasons, to also fix the discharge end of the housing in the direction of the longitudinal axis. The problem then occurs here that the axial expansion of the housing has to be absorbed by the gear and optionally the motor arranged behind it. For this purpose, complex multi-ball bearings are used in practice for the gear and optionally the drive motor to make these displaceable as a whole.
A screw machine according to the generic type is known from US 2006/0076705 A1. To compensate thermally caused longitudinal expansions a gap is provided here between the housing of the screw machine and an attachment housing of the gear, so the housing of the screw machine can thermally expand toward the gear. A defined position between the gear and housing of the screw machine cannot be achieved by this.
It is known from EP 1 990 176 A1 to configure a slide connection between an extruder and a melt line adjoining the latter.